Getting a reference to an internal data structure is not thread-safe. DataSources which wish to protect their data from concurrent access may return the null reference with this method. All calls to rvalue() must first check whether they do not return null.

Getting a reference to an internal data structure is not thread-safe. DataSources which wish to protect their data from concurrent access may return the null reference with this method. All calls to set() must first check whether they do not return null.

Member Data Documentation

We aren't using boost::shared_ptr, because boost::intrusive_ptr is better, exactly because it can be used with refcounts that are stored in the class itself. Advantages are that the shared_ptr's for derived classes use the same refcount, which is of course very much desired, and that refcounting happens in an efficient way, which is also nice :)